利用长江口现代潮滩沉积硅藻建立海平面转换函数的尝试

摘要

在高精度海平面定量重建研究中，有孔虫、硅藻等海洋微体古生物转换函数技术是近10余年随着计算机技术发展而快速兴起的一项新技术，已成为欧美地区研究海平面变化的不可或缺的定量手段之一，而其在中国沿海地区全新世海平面定量重建中的应用却屈指可数。以硅藻为例，详细介绍了建立其与海平面之间的转换函数的过程，包括现代表层样采集、统计学分析、误差的可能来源和减小误差的方法。通过在对崇明岛四！港 SY剖面潮滩表层样品的环境因子分析和对硅藻属种的 CCA 排序分析发现，高程对潮滩硅藻属种排序有着很高的解释贡献。随后通过 WA和 WA-PLS 建立模型，四！港 SY 剖面全样 WA-PLS 模型的相关系数（R2_Jack）达到0.9004，预期误差（RMSEP）为12.622，若不考虑潮上带样品 SY1后的转换模型其精度更能达到±10cm。本研究以期带动此项技术在国内的发展，促进高精度海平面定量重建，从而能为沿海地区海岸带管理提供更详实、更具现实指导意义的地质记录。%In the research on quantitative high-resolution sea-level reconstruction,microfossil-based transfer function is a newly and rapidly developed technique assisted by the development of computer tech-nology in the past decade.It has become one of the indispensable methods in sea-level research in manywestern countries.However,its application to reconstructions of the Holocene relative sea-level history in Chinese coasts has been limited.This paper intends to introduce the method of the diatom (as an exam-ple) based sea-level transfer functions,including tidal flat sampling strategy,statistical analysis,possi-ble prediction errors and reducing-error method.Through analyzing the tidal flat surface samples collected from SY section at Siyao port of Chongming Island and the CCA ordination of diatom species,it was con-cluded that the elevation is the most contributing factor for diatoms sorting among all the environmental pa-rameters.Thus, a transfer function with weighted average (WA ) and weighted average partial least squares (WA-PLS)was used.The correlation (R2_Jack) is 0.9 and the RMSEP is±1 2.6cm with all samples of SY section at Siyao port.The precision may be improved to ±1 0cm when the sample from a su-pratidal site (sample of SY1 ) is excluded.This research will push such quantitative methods forwards to a higher level in high-resolution sea-level reconstructions that can help produce high-quality geological re-cords to aid coastal management of China.